This paper examines the long-term impact on public lands of human-powered adventure activities. These activities take individuals into federal- or state-owned wild areas to enjoy backpacking, hiking, camping, and a wide variety of sports. Trends in supply and demand for outdoor opportunities are explored. Factors influencing demand include growing population, an increase in per capita income, more accessible transportation, and more leisure time. Lack of wilderness "supply" can be caused by overuse, insufficient funding, inadequate management, lack of facilities, lack of staff, and lack of political support and legislation. In order to ensure that the supply of wild lands continues to meet the increasing demand, the education of professional outdoor leaders must include environmental activist skills, critical thinking skills, and environmental ethics. Expansion of the college curriculum to include education for environmental activism could create a "prairie fire of action" to protect the wilderness--our outdoor classroom. Case studies describe two programs that address environmental ethics: the Four Corners School of Outdoor Education in Utah, and the Environmental Studies program at the University of Montana. Contains 16 references. (SAS)